This is a library of perfboard and single-sided PCB effect layouts for guitar and bass. I'm not an electrical engineer by any stretch of the imagination, just a DIY'er who likes drawing layouts. It is meant for the hobbyist (so commercial use of any of these layout is not allowed without permission) and as a way to give back to the online DIY community.

Wednesday, November 23, 2016

Demeter Tremulator

Here's a great sounding tremolo circuit from Demeter–the Tremulator. It's an optical trem, using a VTL5C1. That part can be replaced with an LED and a LDR (600Ω on/50M off) combo. Also, the diodes used in the originals are 1N5229 4.3v zenners, though you can use other zenners up to 5.1v. Here's the schematic for reference.


  1. Cool! I like the smoothness. Def going to give this one a go. Thanks for the layout.

  2. It's verified. I subbed TL071 for 061, LF356 for 351.
    VTL5C1 works on it, but LED/LDR combo, 5mm green undiffused LED and LDR with dark resistance of 10M, is OK as well. I have found no apparent difference between Vactrol and the combo.

    1. Awesome! Thanks for verifying and the build notes too.

    2. What do you mean by undiffused? You mean the ones with the green or transparent acrylic? because they both have the green light obviously thanks anyway

    3. The transparent kind. They're a tad brighter than the diffused types.

  3. The trimport seems to be too subtle with 5k value, but when the value increased it works on very unique way. In my case, somewhere between 500k and 1M would be fine and worth moving it externally. For builders of this pedal, I recommend to try some values before soldering it.

  4. Hello. Where do I connect the led to show the oscillation of the "ON" effect? In the JOYO tremolo there is a trimpot option to adjust the volume and also an option to change the shape of the wave. Would it be possible to add these features in the tremulator? Thanks

  5. Not sure how useful a volume control would be on this as it's output is about unity. But for the LED I'd trying putting another 1k resistor in parallel with the 1k resistor just to the left of the LF351. Then connect that resistor to the anode (+) of the LED you're adding with the cathode (-) going to ground.

  6. Already made it on a breadboard. So far for me, the best DIY tremolo. I like the range of speed and depth. Got 2 problems at the moment though. First, a big volume loss second, a faint ticking at max level but not much a bother to me.
    Replacement of components:
    TL072 insted of LF442
    TL091 instead of LF351
    4148 instead of 4.3vzener
    Led/ldr combo
    10k trimmer instead of 5k
    Thank You....